import dayjs from 'dayjs'
import { ref,computed,onUnmounted } from 'vue'
export const useCountDown = () => {
    //1.响应式数据
    let timer = null
    const time = ref(0)

    //格式化时间 为xx分xx秒
    const formatTime = computed(() => dayjs.unix(time.value).format('mm分ss秒'))
    //2.开启倒计时的函数
    const start = (currentTime) => {
        time.value = currentTime
        timer = setInterval(() => {
            time.value-- 
        },1000)
    }

    //组件销毁时清除定时器
    onUnmounted(() => {
        //确保timer不为null或者undefined的时候调用clearInterval函数，否则可能报错
        timer&&clearInterval(timer)
    })

    return {
        formatTime,
        start
    }
}